content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.*;
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import io.reactivex.common.*;
  import io.reactivex.common.disposables.CompositeDisposable;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.Function;
  import io.reactivex.common.internal.disposables.DisposableHelper;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.observable.ObservableSource;
  import io.reactivex.observable.Observer;
  import io.reactivex.observable.extensions.SimplePlainQueue;
  import io.reactivex.observable.internal.observers.QueueDrainObserver;
  import io.reactivex.observable.internal.queues.MpscLinkedQueue;
  import io.reactivex.observable.internal.utils.QueueDrainHelper;
  import io.reactivex.observable.observers.*;
  
  public final class ObservableBufferBoundary<T, U extends Collection<? super T>, Open, Close>
  extends AbstractObservableWithUpstream<T, U> {
      final Callable<U> bufferSupplier;
      final ObservableSource<? extends Open> bufferOpen;
      final Function<? super Open, ? extends ObservableSource<? extends Close>> bufferClose;
  
      public ObservableBufferBoundary(ObservableSource<T> source, ObservableSource<? extends Open> bufferOpen,
                                      Function<? super Open, ? extends ObservableSource<? extends Close>> bufferClose, Callable<U> bufferSupplier) {
          super(source);
          this.bufferOpen = bufferOpen;
          this.bufferClose = bufferClose;
          this.bufferSupplier = bufferSupplier;
      }
  
      @Override
      protected void subscribeActual(Observer<? super U> t) {
          source.subscribe(new BufferBoundaryObserver<T, U, Open, Close>(
                  new SerializedObserver<U>(t),
                  bufferOpen, bufferClose, bufferSupplier
                  ));
      }
  
      static final class BufferBoundaryObserver<T, U extends Collection<? super T>, Open, Close>
      extends QueueDrainObserver<T, U, U> implements Disposable {
          final ObservableSource<? extends Open> bufferOpen;
          final Function<? super Open, ? extends ObservableSource<? extends Close>> bufferClose;
          final Callable<U> bufferSupplier;
          final CompositeDisposable resources;
  
          Disposable s;
  
          final List<U> buffers;
  
          final AtomicInteger windows = new AtomicInteger();
  
          BufferBoundaryObserver(Observer<? super U> actual,
                  ObservableSource<? extends Open> bufferOpen,
                  Function<? super Open, ? extends ObservableSource<? extends Close>> bufferClose,
                          Callable<U> bufferSupplier) {
              super(actual, new MpscLinkedQueue<U>());
              this.bufferOpen = bufferOpen;
              this.bufferClose = bufferClose;
              this.bufferSupplier = bufferSupplier;
              this.buffers = new LinkedList<U>();
              this.resources = new CompositeDisposable();
          }
          @Override
          public void onSubscribe(Disposable s) {
              if (DisposableHelper.validate(this.s, s)) {
                  this.s = s;
  
                  BufferOpenObserver<T, U, Open, Close> bos = new BufferOpenObserver<T, U, Open, Close>(this);
                  resources.add(bos);
  
                  actual.onSubscribe(this);
  
                  windows.lazySet(1);
                  bufferOpen.subscribe(bos);
              }
          }
  
          @Override
          public void onNext(T t) {
              synchronized (this) {
                  for (U b : buffers) {
                      b.add(t);
                  }
              }
          }
  
          @Override
          public void onError(Throwable t) {
              dispose();
              cancelled = true;
              synchronized (this) {
                  buffers.clear();
              }
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (windows.decrementAndGet() == 0) {
                  complete();
              }
          }
  
          void complete() {
              List<U> list;
              synchronized (this) {
                  list = new ArrayList<U>(buffers);
                  buffers.clear();
              }
  
              SimplePlainQueue<U> q = queue;
              for (U u : list) {
                  q.offer(u);
              }
              done = true;
              if (enter()) {
                  QueueDrainHelper.drainLoop(q, actual, false, this, this);
              }
          }
  
          @Override
          public void dispose() {
              if (!cancelled) {
                  cancelled = true;
                  resources.dispose();
              }
          }
  
          @Override public boolean isDisposed() {
              return cancelled;
          }
  
          @Override
          public void accept(Observer<? super U> a, U v) {
              a.onNext(v);
          }
  
          void open(Open window) {
              if (cancelled) {
                  return;
              }
  
              U b;
  
              try {
                  b = ObjectHelper.requireNonNull(bufferSupplier.call(), "The buffer supplied is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  onError(e);
                  return;
              }
  
              ObservableSource<? extends Close> p;
  
              try {
                  p = ObjectHelper.requireNonNull(bufferClose.apply(window), "The buffer closing Observable is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  onError(e);
                  return;
              }
  
              if (cancelled) {
                  return;
              }
  
              synchronized (this) {
                  if (cancelled) {
                      return;
                  }
                  buffers.add(b);
              }
  
              BufferCloseObserver<T, U, Open, Close> bcs = new BufferCloseObserver<T, U, Open, Close>(b, this);
              resources.add(bcs);
  
              windows.getAndIncrement();
  
              p.subscribe(bcs);
          }
  
          void openFinished(Disposable d) {
              if (resources.remove(d)) {
                  if (windows.decrementAndGet() == 0) {
                      complete();
                  }
              }
          }
  
          void close(U b, Disposable d) {
  
              boolean e;
              synchronized (this) {
                  e = buffers.remove(b);
              }
  
              if (e) {
                  fastPathOrderedEmit(b, false, this);
              }
  
              if (resources.remove(d)) {
                  if (windows.decrementAndGet() == 0) {
                      complete();
                  }
              }
          }
      }
  
      static final class BufferOpenObserver<T, U extends Collection<? super T>, Open, Close>
      extends DisposableObserver<Open> {
          final BufferBoundaryObserver<T, U, Open, Close> parent;
  
          boolean done;
  
          BufferOpenObserver(BufferBoundaryObserver<T, U, Open, Close> parent) {
              this.parent = parent;
          }
          @Override
          public void onNext(Open t) {
              if (done) {
                  return;
              }
              parent.open(t);
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              done = true;
              parent.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              parent.openFinished(this);
          }
      }
  
      static final class BufferCloseObserver<T, U extends Collection<? super T>, Open, Close>
      extends DisposableObserver<Close> {
          final BufferBoundaryObserver<T, U, Open, Close> parent;
          final U value;
          boolean done;
          BufferCloseObserver(U value, BufferBoundaryObserver<T, U, Open, Close> parent) {
              this.parent = parent;
              this.value = value;
          }
  
          @Override
          public void onNext(Close t) {
              onComplete();
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              parent.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              parent.close(value, this);
          }
      }
  }
  